The present invention relates to a light controlling device for a motor vehicle, and more particularly, to a device comprising an operating switch and electronic apparatus assigned to the operating switch for supplying current to a multiplicity of lamps of an operating light system and having for each lamp function at least one controlled switching component for clock-controlled supplying of current to an assigned lamp.
It is known technology that the functioning of a light unit, such as for example the dipped headlight or rear brake light, is monitored, and a defect or a malfunction leads to an indication via, for example, a warning lamp.
DE 43 08 514 A1 discloses a vehicle headlamp control system which has a control circuit which controls the illumination intensity and the operation of the vehicle headlamps when starting the vehicle engine. The control circuit operates such that the switching transistors, via which the individual headlamps are connected to the on-board electrical system, are driven by switching pulses. The pulse duty factors of the respective driver pulse streams are set in the way required for desired illumination intensities of the headlamps.
EP 02 79 168 B1, which corresponds to DE 37 02 517 A1, further discloses a circuit arrangement suitable for supplying power to vehicle loads. The circuit comprises switchgear which is driven by a central unit via a ring-bus system and connects to the supply corresponding loads of a supply current conductor of the bus system. The load currents are monitored in order to detect any short-circuits.
DE 41 36 427 A1 discloses an electronically controlled motor vehicle lighting system in which the switching on and off of the vehicle lighting, and also the luminosity regulation of the headlamps, are controlled automatically according to the light, visibility and traffic conditions by electronics with associated photoelectronic components for light measurement.
It is an object of the present invention to provide a motor vehicle light controlling device which allows the energy balance of the on-board electrical system to be improved and better utilizes the conductor material used.
This object has been achieved in a motor vehicle light controlling device according to the present invention by dividing the device into a light switch module and a rear lamp module, with clock control distributed over both modules in order to influence the lamp currents of the operating lights of the vehicle. That is, to be precise, on the one hand, to lower the luminosity of certain lights when required and, on the other hand, to increase the on-board system voltage temporarily without the luminosity or lamp power changing as a result. The latter is of interest, for example, for the brief driving of electrical heating elements or servo-motors, in order to achieve an advantageously high utilization of conductor material used.
For instance, the lamps for driving light when stationary can be dimmed to a light power corresponding to the customary parking light. Or, in the event of failure of a lamp or of a circuit for driving light, the corresponding headlamp can be supplied with current clock-controlled for lower light power, so that an emergency driving light function can be realized. Furthermore, the clock output stages can be used at the same time to realize an electronic protection of the individual lamp circuits, so that it is possible to dispense with a considerable number of conventional, exchangeable fuse elements as well as the space required for installing them. Another feature within the scope of the present invention allows the automatic switching on of lights according to requirements by a light sensor signal of a light sensor, for example in the lower boundary surface of an outside rear-view mirror.
A major advantage of the device of the present invention is a reduction in the number of required lines or cable sets to be kept in stock and the improvement in the energy balance of the on-board system, by virtually eliminating the power loss which occurs at series resistors when the latter are used for dimming operating lights.